AIO Customer sucked on my ear

I'm a server at a medium-fancy chain restaurant. It's a mostly good job, good tips. However, my boss pushes boundaries often with what he allows the guests to get away with. I understand being hospitable, but he almost seems to reward bad behaviour. Today, it went too far.

A 4 top was seated in my section, not regulars, three men and one lady. Nothing out of the ordinary yet. But one of the men, who I'll call Creep, is off the bat super off putting towards me when i start serving them. He makes a comment about me needing to smile more and that I could use a good tip. It's stuff I've heard before, but it wasn't a good vibe. No one at the table seemed to think anything was wrong though. I'm a little grossed out already, but it's usually easier to ignore it and just get through without making trouble.

So I come back with their drinks, and I'm sort of leaning over the table to pass the lady in the back left of the booth her drink. As I'm doing that, Creep leans over and puts his mouth on my ear and sucks on it. It was so disgusting, i can still hear the sound eugh. I jump backward, before basically running to the back to talk to my boss. I tell him what happened, fully expecting him to do SOMETHING. But hes not concerned, says he knows them and that they're harmless, and not to take it seriously. I immediately took off my apron, grabbed my keys and drove home. I'm getting calls and texts from boss, he doesn't seem too angry but he's definitely upset that I walked out over what he sees as nothing. Am I overreacting?